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Purse SeineFishing Procedures & Gear

Introduction

30% global catch

Watson et al. 2004

Introduction

30% global catch Wall of net encircles pelagic fish

Introduction

30% global catch Wall of net encircles fish Usually fish close to surface Inland, coastal & high-seas

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Introduction

30% global catch Wall of net encircles fish Usually fish close to surface Inland, coastal & high-seas Small & large vessels

http://whyfiles.org

http://afishblog.com/

http://www.inpesca.com

Introduction

30% global catch Wall of net encircles fish Usually fish close to surface Inland, coastal & high-seas Small & large vessels Small & large fish

Introduction - impacts

No bottom impact Bycatch – mammals, turtles, sharks Juvenile fish issues with FADs

NOAA Photo Library

http://afishblog.com/

©WWF/Helene Petit

http://afishblog.com/

Objectives

Describe how purse seine gear works Explain how marine mammals can be

released safely List 4 components of a purse seine

and 2 pieces of specialized equipment Demonstrate ability to complete the

gear description form

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Sampling priorities

1. Record vessel activity continuously each day on board;

2. Estimate total catch for each gear deployment;3. Collect random samples for catch composition of

each set and document species retained and discarded;

4. Describe all floating objects sighted, especially those involved in a fishing set;

5. Subsample catch for lengths;6. Record all sightings and interactions with marine

mammals and sea turtles;7. Record fishing gear characteristics.

Activity #1

Grab a piece of scrap paper Complete as much of the following

diagram as you can You have 3 minutes

Gear description – float line (cork line)

©Yogesh Naik

© Craig Knickle

http://www.ongoy.biz

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Gear description – lead line, purse line, purse rings

BenYami 1987

Gear description

www.seattlemarine.net

Jon Rowley/Flickr.com

Lead line

Purse line

Purse ring

Other EquipmentPurse seining –locating fish

lizardwisdom/flickr.com

lizardwisdom/flickr.com

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Purse seining – locating fish - cueshttp://www.sanford.co.nz/ourfleet/tunavessels/

http://oceanaerials.com/Tuna.htmlhttp://forums.marlinmag.com/

Purse seining – locating fish

http://forman.en.ec21.com

http://tunaseiners.com

www.simrad.com

Bird radar

Sonar

Purse seining – how it works

Gear deployment Gear retrieval

Animation: www.montereybayaquarium.org

Purse seining – how it works

Video #1 Video #2 (alternate)

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Gear retrieval – net hauling systems

“Duplex” style double sheave power block. (Figure 13 in Itano 2003)

Double block systemhttp://whyfiles.org

Triplex power block (Gillett) (Figure 14 in Itano 2003)

Petrel_V-type Netwinch (http://www.petrel.co.za/default.asp)

Power blockhttp://tunaseiners.com/blog/es/2009/02/king-of-purse-seine-fishing/

Gear retrieval – net hauling systems

Retractable deck mountedpower block (Figure 19 in Itano 2003)

Sacking up with rail roller andpinch hauler on Japanese group seiner (Figure 23 in Itano 2003)

Side rail rollers © Alex Hofford (http://www.alexhoffordphotography.com)

Gear retrieval – purse line winch & capstan

CMT (http://www.nauticexpo.com)Rapp Hydema (http://www.nauticexpo.com)

KARM (http://www.nauticexpo.com)

CMT Capstan (http://www.cmtwinches.com/)

Gear retrieval – purse rings

Old style steel rings with chain bridles (Figure 3 in Itano 2003)

Securing rings to the ring stripper prior to net retrieval (Figure 4 in Itano 2003) Stainless steel roller snap rings

(Figure 5 in Itano 2003)

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©2009 Alex Hofford

lizardwisdom/flickr.com

Marine mammals

Backdown procedure

NRC 1992

Marine mammals

Backdown procedure Dolphin safety panel

Floating objects

FAO Cape Verde FAD installation: http://www.fao.org/english/newsroom/highlights/2001/010102-e.htm

IFREMER/M Toquet

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Gear description form Gear description form

Gear description form

Total length of net = count of handholds * distance between handholds

Handholds

Gear description form

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Gear description form

Net depth = # strips * strip height

8 Strips

Gear description form

Gear description form

StretchedMeshOpening -Diamond Mesh

Modified from Ferro & Xu 1996

Knotted braided polyethylene meshhttp://www.haverford.com.au

Knotless twisted nylon meshhttp://www.haverford.com.au

Gear description form

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Gear description form Gear description form

Questions Practice exercise – 15 minutes Additional Information:

Purseline: 8mm Spectra™

Summary

Describe how purse seine gear works Explain how marine mammals can be

released safely

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http://www.bdoutdoors.com/ Rapp Hydema (http://www.nauticexpo.com)http://tunaseiners.com

References Ben-Yami, M. 1987. Purse-seining with small boats. FAO Training

Series No. 13, FAO, Rome. Ferro, R. S. T., and L. Xu. 1996. An investigation of three methods

of mesh size measurement. Fisheries Research 25:171-190. Itano, D.G. 2003. Documentation and classification of fishing gear

and technology on board tuna purse seine vessels. 16th Meeting of the Standing Committee on Tuna and Billfish, Mooloolaba, Australia, 9-16 July 2003. SCTB16-FTWG-3.

National Research Council Committee on Reducing Porpoise Mortality from Tuna Fishing. 1992. Dolphins and the Tuna Industry. National Academy Press, Washington D.C.

Seret, B. 1981. Poissons de mer de l'ouest africain tropical, Initiation-Documentation Techniques No. 49. ORSTOM, Paris.

Watson, R., E. Hoshino, J. Beblow, C. Revenga, Y. Kura, and A. Kitchingman. 2004. Fishing Gear Associated With Global Marine Catches. Fisheries Centre Research Reports 12.